File Name: origin and conduction of heartbeat .zip
- The development of cardiac rhythm
- Origin of heart beat and its conduction is represented by
- The Conducting System of the Heart
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The development of cardiac rhythm
The cardiac conduction system is a collection of nodes and specialised conduction cells that initiate and co-ordinate contraction of the heart muscle. It consists of:. In this article, we shall look at the anatomy of the cardiac conduction system — its structure, function and clinical correlations. These pacemaker cells can spontaneously generate electrical impulses. The wave of excitation then passes from the atrioventricular node into the atrioventricular bundle. It descends down the membranous part of the interventricular septum, before dividing into two main bundles:. Fig 2 — Overview of the individual components of the heart conduction pathway.
Origin and conduction of heart beat. The heart in human is myogenic cardiomyocytes can produce spontaneous rhythmic depolarisation that initiates contractions. The sequence of electrical conduction of heart is shown in Figure 7. The cardiac cells with fastest rhythm are called the Pacemaker cells, since they determine the contraction rate of the entire heart. Two special cardiac muscle fibres originate from the auriculo ventricular node and are called the bundle of His which runs down into the interventricular septum and the fibres spread into the ventricles.
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Origin of heart beat and its conduction is represented by
Heart has intrinsic system whereby muscle contracts and relax without the involvement of brain. SA node is a small, flattened mass of neuromuscular tissue, about 3mm wide, 15mm long and 1mm thick. It is situated near the opening of superior venacava in right atrium. Sinus nodal fibers connects directly with the atrial muscle fibers so that any action potential that begins in the sinus node transmits immediately into atrial muscle wall. The fibers of SA node has ability of self excitation and control the rate of entire heartbeat. The fibers of SA node have high concentration of Sodium ions in extracellular fluid and negative charges inside the nodal fibers. Ultimately at threshold approx.
The cardiovascular system is the first organ system to form and function in the developing embryo. In the early stages the heart is a slow conducting, single tubular structure generating an even peristaltic contraction. During embryogenesis it then develops into a four chambered heart with synchronous contraction for a dual circulation. These synchronous contractions of the atrial and ventricular chambers are dependent on the development of high conduction velocities resulting in alternating slow and fast conducting segments. In the early embryonic heart tube, an ECG similar to that of an adult has been recorded. This indicates the electrical activity of sequentially activated heart chambers, 1 so demonstrating the functioning of the cardiac conduction system CCS , before any morphological development can be distinguished. Throughout the developmental process the heart must maintain its rhythmical contractions through coordinated activation of the myocardium.
The normal cardiac-conduction-system is responsible for the contraction of the heart muscle. They determined that the origin of the heartbeat occurred in a.
The Conducting System of the Heart
If your institution subscribes to this resource, and you don't have a MyAccess Profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus. Please consult the latest official manual style if you have any questions regarding the format accuracy. After studying this chapter, you should be able to:. Describe the structure and function of the conduction system of the heart and compare the action potentials in each part. List the principal early and late ECG manifestations of myocardial infarction and explain the early changes in terms of the underlying ionic events that produce them.